<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <script src="https://cdn.staticfile.org/react/16.4.0/umd/react.development.js"></script>
    <script src="https://cdn.staticfile.org/react-dom/16.4.0/umd/react-dom.development.js"></script>
    <!-- 生产环境中不建议使用 -->
    <script src="https://cdn.staticfile.org/babel-standalone/6.26.0/babel.min.js"></script>
</head>

<body>
    <div id="app"></div>

</body>
<script type="text/babel">

    class Parent extends React.Component{
        constructor(){
            super()
            this.state={
                msg:'',
            }
        }

        show(v){
            // console.log(this)
            this.setState({
                msg:v
            })
        }

        render(){
            return (<div>
                        <h1>我是父組件 => {this.state.msg }</h1>
                        <Child getMsg={this.show.bind(this)}/>
                    </div>)
        } 
    }

    class Child extends React.Component{
        constructor(){
            super()
            this.state ={
                msg: '我是子组件的数据'
            }
        }
        
        componentWillMount(){
            this.props.getMsg(this.state.msg)
        }

        render(){
            return (
                    <h1>我是子组件 => {this.state.msg}</h1>
                    )
        }
    }

    ReactDOM.render(<Parent/>,app)
    
</script>

</html>